/Engine/Source/Runtime/AudioExtensions/Public/IAudioEndpoint.h
METHODS USED BY IMPLEMENTATIONS OFIAudioEndpoint: This is used by theIAudioEndpointimplementation to poll buffered audio to process or send to the endpoint. Note that this is NOT thread safe ifEndpointRequiresCallback()is overridden to return true. If that is the case, use an override of OnAudioCallback instead.
[out] the number of samples polled from this thing.
int32 PopAudio ( float * OutAudio, int32 NumSamples )